The reduction of Eu3+ to Eu2+ in air and luminescence properties of Eu2+ activated ZnO-B2O3-P2O5 glasses

A valence change from Eu3+ to Eu2+ was observed in the europium ion-doped ZnO-B2O3-P2O5 glasses prepared at high temperature in air. The fluorescence emission spectrum of the sample consists of a broad emission band ascribed to the 5d-4f transition of Eu2+ ion and sharp emission peaks assigned to the transitions of D-5(0)-F-7(J) (J = 0, 1, 2, 3, and 4) of Eu3+ ion, indicating that part of Eu3+ can be reduced into Eu2+ in the glass. A charge compensation model is proposed. The rigid tetrahedral network structure of glasses plays an important role in stability of Eu2+. The fabrication conditions are also studied. (c) 2006 Published by Elsevier B.V.